Popular self-help writer Tim Ferriss said in his book The Four-Hour Body (Harmony, 2010) that he lost 20 pounds in one month without exercise by, in part, eliminating "anything that is white, or can become white" — products that usually contain gluten.

"It's the diet du jour," says Julie M. Jones, a professor of dietetics at St. Catherine's University in St. Paul, Minnesota, and an advisor to The Grain Foods Foundation. She also works with other scientists to develop gluten-free products.

A number of popular diets have recently advocated dropping wheat and other grains. Paleo dieters argue that grains are relatively recent additions to the human diet, and aren't as well suited to our digestive systems as animal meat, fruits, and vegetables. Other low-carb diets like the Atkins diet also advocate reducing grains to spur weight-loss.

"Basically these are low-carb diets, where wheat is the hook," Jones told Business Insider.

But is this smart?

While some people should avoid gluten for health reasons, the number so far is relatively small. On top of the 1 percent of Americans that have Celiac disease, just half a percent more suffer from a wheat allergy, which is specific to that grain.

People who suffer from Celiac disease are often lacking crucial vitamins, especially B vitamins. It can be difficult to diagnose without a biopsy. Almost half of all adults and more than half of all children with the disease showed no symptoms of the disease at all, according to information published by the University of Chicago Medical Center.

The highest estimates suggest 6 percent of the U.S. population may some kind of trouble with gluten — which means 94 percent can tolerate gluten just fine and should think and plan carefully before redlining it from their diets. The biggest problem — and this goes for any diet — is that cutting out gluten could leave you severely deficient in several nutrients and fiber, Jones said.

"The people who advocate low-carb diets say you can get fiber from fruits and vegetables, but, well, we aren't eating those either."

Americans already get only a fraction of the required amount of fiber — only 4 percent get enough of it, and less than 1 percent of men between the ages of 14 and 50 meet the fiber requirement. Most people are way under the established guidelines of about 25 grams per day for women and almost 40 grams per day for men.

"Most people's average intake is 13 grams a day," Jones said. "The average gluten-free diet has only six grams per day." People on low-carb diets eat fruit and vegetables to gain all of their fiber, but grains and cereals provide more efficient forms of fiber than the fruit fiber pectin.

Ultimately, any weight lost on any of these diets is probably coming from a reduction in calories, rather than from the elimination of any one ingredient, Jones said.

People who do decide to drop wheat should look for other alternative whole grains, like whole grain sorghum, buckwheat and quinoa.